Numerous investigators have studied the influence of magnetization on the dynamics of fluidized solids in batch bed operations. An early account of this phenomenon was reported by M. V. Filippov [Applied Magnetohydrodynamics, Trudy Instituta Fizika Akad. Nauk., Latviiskoi SSR 12:215-236 (1960): Zhurnal Tekhnicheskoi Fiziki, 30, (9): 2081-1084 (1960); Izvestiya Akad. Nauk., Lativvskoi SSR, 12 (173): 47-51 (1961); Izvestiya Akad. Nauk., Latviiskoi SSR, 12: 52-54 (1961); and Aspects of Magnetohydrodynamics and Plasma Dynamics, Riga (1962), Izvestiya Akad. Nauk., Latviiskoi SSR, pp. 637-645]. Subsequent investigators have described the influence that magnetization exerts on pulsations, heat transfer, structure, and other characteristics of magnetized and fluidized solids in batch bed operations. A partial review of such studies has been presented by Bologa and Syutkin [Electron Obrab Mater, 1: 37-42 (1977)]. Ivanov and co-workers have described some benefits of applying a magnetic field to fluidized ferromagnetic solids during ammonia synthesis and noted some of the bed characteristics during said synthesis [see British Pat. No. 1,148,513 and numerous publications by the same authors, e.g., Ivanov et al, Kinet. Kavel, 11 (5): 1214-1219 (1970); Ivanov et al, Zhurnal Prikladnoi Khimii, 43, 2200-2204 (1970); Ivanov et al, Zhurnal Prikladnoi Khimmi, 45: 248-252 (1972); Ivanov et al, Chemical Industry, 11, 856-585 (1974); Shumkov et al, Zhurnal Prikladnoi Khimii, 49 (11): 2406-2409 (176)]. In addition, various means for operating magnetic fields to stabilize a bed of magnetizable solids have been disclosed in U.S. Pat. Nos. 3,440,731; 3,439,899; 4,132,005 and 4,143,469; and Belgium Pat. No. 865,860.
Recently, R. E. Rosensweig reported a number of features relating to magnetically stabilized fluidized magnetizable solids and provided a systematic interpretation of the phenomenon [Science, 204: 57-60 (1979), Ind. Eng. Chem. Fundam., 18, (3): 260-269 (1979), Lucchesi et al, Proc. of the 10th World Petroleum Congress, Bucharest, Romania, 1979, 4, Heyden and Sons, Philadelphia, Pa. (1979) and U.S. Pat. Nos. 4,115,927 and 4,136,016]. These publications noted the quiescent, fluid-like state of the magnetically stabilized fluidized bed (MSB), particularly a bed totally free of bubbles or pulsations when subjected to a uniform magnetic field applied colinear with the flow of the fluidizing fluid. Bed stabilization results in a non-bubbling fluid state having a wide range of operating velocities (denoted as superficial fluid velocities) which range between (a) a lower limit defined by the normal minimum fluidization superficial fluid velocity (U.sub.mf) required to fluidize the bed in the absence of the applied magnetic field, i.e. magnetic effects, and (b) an upper limited defined by the superficial fluid velocity (U.sub. T) required to cause time-varying fluctuations of pressure difference through the stabilized bed during continuous fluidization in the presence of the applied magnetic field. In U.S. Pat. No. 4,115,927, Rosensweig discloses that the stably fluidized solids resemble a liquid such that solids transport is facilitated while the pressure drop is limited to that of a fluidized bed. Also the backmixing normally associated with conventional fluidized bed processes is absent. Furthermore, while U.S. Pat. No. 4,115,927 suggests the possibility of transporting the solids from the containing vessel (see column 8 lines 58-59 and column 21 lines 17-24), none of the experiments involved continuous throughput of bed solids. In addition, neither Rosensweig nor Filippov described operations near the locus of transition between the bubbling and stabilized regions in beds having continuous solids addition and removal. Therefore, the boundaries of the regions defined by Rosensweig and by Filippov do not concern processes where solids are added and removed continuously.
More recently, U.S. Pat. No. 4,247,987, the Belgian counterpart of which was granted on Mar. 29, 1981 as Belgian Pat. No. 885,390, described the countercurrent operation of a magnetically stabilized bed with continuous solids addition and removal at or substantially near the locus of transition between the bubbling and stabilized regions of the bed in order to increase bed fluidity. However, patentees disclose only countercurrent operations--no mention is made of solids transport transverse to the flow of the fluidizing fluid.